/*
 * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package java.net;

import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;

/**
 * This stream extends FileOutputStream to implement a
 * SocketOutputStream. Note that this class should <b>NOT</b> be
 * public.
 *
 * @author Jonathan Payne
 * @author Arthur van Hoff
 */
class SocketOutputStream extends FileOutputStream {

  static {
    init();
  }

  private AbstractPlainSocketImpl impl = null;
  private byte temp[] = new byte[1];
  private Socket socket = null;

  /**
   * Creates a new SocketOutputStream. Can only be called
   * by a Socket. This method needs to hang on to the owner Socket so
   * that the fd will not be closed.
   *
   * @param impl the socket output stream inplemented
   */
  SocketOutputStream(AbstractPlainSocketImpl impl) throws IOException {
    super(impl.getFileDescriptor());
    this.impl = impl;
    socket = impl.getSocket();
  }

  /**
   * Returns the unique {@link java.nio.channels.FileChannel FileChannel}
   * object associated with this file output stream. </p>
   *
   * The {@code getChannel} method of {@code SocketOutputStream}
   * returns {@code null} since it is a socket based stream.</p>
   *
   * @return the file channel associated with this file output stream
   * @spec JSR-51
   * @since 1.4
   */
  public final FileChannel getChannel() {
    return null;
  }

  /**
   * Writes to the socket.
   *
   * @param fd the FileDescriptor
   * @param b the data to be written
   * @param off the start offset in the data
   * @param len the number of bytes that are written
   * @throws IOException If an I/O error has occurred.
   */
  private native void socketWrite0(FileDescriptor fd, byte[] b, int off,
      int len) throws IOException;

  /**
   * Writes to the socket with appropriate locking of the
   * FileDescriptor.
   *
   * @param b the data to be written
   * @param off the start offset in the data
   * @param len the number of bytes that are written
   * @throws IOException If an I/O error has occurred.
   */
  private void socketWrite(byte b[], int off, int len) throws IOException {

    if (len <= 0 || off < 0 || off + len > b.length) {
      if (len == 0) {
        return;
      }
      throw new ArrayIndexOutOfBoundsException();
    }

    FileDescriptor fd = impl.acquireFD();
    try {
      socketWrite0(fd, b, off, len);
    } catch (SocketException se) {
      if (se instanceof sun.net.ConnectionResetException) {
        impl.setConnectionResetPending();
        se = new SocketException("Connection reset");
      }
      if (impl.isClosedOrPending()) {
        throw new SocketException("Socket closed");
      } else {
        throw se;
      }
    } finally {
      impl.releaseFD();
    }
  }

  /**
   * Writes a byte to the socket.
   *
   * @param b the data to be written
   * @throws IOException If an I/O error has occurred.
   */
  public void write(int b) throws IOException {
    temp[0] = (byte) b;
    socketWrite(temp, 0, 1);
  }

  /**
   * Writes the contents of the buffer <i>b</i> to the socket.
   *
   * @param b the data to be written
   * @throws SocketException If an I/O error has occurred.
   */
  public void write(byte b[]) throws IOException {
    socketWrite(b, 0, b.length);
  }

  /**
   * Writes <i>length</i> bytes from buffer <i>b</i> starting at
   * offset <i>len</i>.
   *
   * @param b the data to be written
   * @param off the start offset in the data
   * @param len the number of bytes that are written
   * @throws SocketException If an I/O error has occurred.
   */
  public void write(byte b[], int off, int len) throws IOException {
    socketWrite(b, off, len);
  }

  /**
   * Closes the stream.
   */
  private boolean closing = false;

  public void close() throws IOException {
    // Prevent recursion. See BugId 4484411
    if (closing) {
      return;
    }
    closing = true;
    if (socket != null) {
      if (!socket.isClosed()) {
        socket.close();
      }
    } else {
      impl.close();
    }
    closing = false;
  }

  /**
   * Overrides finalize, the fd is closed by the Socket.
   */
  protected void finalize() {
  }

  /**
   * Perform class load-time initializations.
   */
  private native static void init();

}
